Some time ago I posted an Idea called "Prion Poison Prevention" (see link), because it seemed to me that prions pose a unique threat that needed to be seriously addressed. Today it occurred to me that because prions exist and are bad, misuse of them is likely to be inevitable. So I am posting this
more for the criminal investigation squads, than for the criminals. (There may also be a better place here on the HalfBakery for it, but I don't know where yet.)

If you don't already know, prions are an unusual brain protein that can exist in at least two different shapes. Since the functioning of a protein depends a great deal on its shape, it happens that prions of one shape are not usefully functional. However, that particular shape is still functional in a horrible way: it can cause a properly-shaped and functional prion to become distorted into the useless shape! When this happens for a significant time in the brain, literal holes develop in brain tissue and mental functions diminish until death occurs. There is no cure.

The next bad thing about malformed prions is that they are biologically pretty stable. If an animal has died from bad prions, and it is processed to feed other animals (including humans), then those prions can survive both cooking and digestion, AND enter the bloodstream and cross the blood-brain barrier and begin their ugly task of converting good prions into bad.

Next, prion diseases tend to work slowly. It can be months after eating some bad prions that they start to have a significant effect. Which brings us to the Idea that prions might make a pretty good murder weapon. Put some in someone's salad, and they won't be detectable to the taste, and they are not poisonous in any ordinary sense, and they are not biologically active like bacteria or even viruses, AND the victim will have no idea how the brain-degenerator was acquired. What can the cops do?

I don't know! Obviously we need Prion Poison Prevention more badly than ever!

The shape of prions, formed by the protein folding and "mutating", makes it resistant to efforts to destroy the prion. I was wonering whether there were enzymes that could unfold the folded protein to either return it to it's normal state or allow it to be destroyed.

I've also read that a prion infecting one species can't easily be introduced into another species, but when it is, it gets more easily transferred in the new species in time.

Not that it has any real relevance to this, I just think it's interesting.

[ldischler], this is something of a dilemma. I am not suggesting USING prions as weapons; I am suggesting that they ARE potential weapons and that inevitably somebody will use them as such. I don't want to encourage that use, even though I know that just by mentioning it somebody will think it worth trying... What I really want here is credit for giving the cops a chance to think of the Idea, "Hmmm, maybe this brain-deterioriation case is actually a homicide."

[bungston], you have something of a point, but with a different inflection, such as [ldischler] suggested and I deliberately avoided, this does indeed qualify as an Idea. And certainly it needs to be independent if people on the outside are following a link, for the purpose of seeing THIS, and not the "Prevention" Idea.

However, I'm
not sure that prions would make a good
murder weapon. I suspect the
transmission rate is very low for non-
human prion (most meat-eaters in the
UK probably ate a fair dose of bovine
PrPsc in their time, but fatalities so far
are very very few), and the latency time
is huge. So, if you lace someone's food
with it, you have a very small chance of
killing them in several years' time (if
they don't happen to have the resistant
genotype).

There's also the
question of
how you get hold of large enough
amounts of PrPsc to raise the odds of
success. You'd need infected livestock
and, preferably, a half-decent kitchen-
lab to enrich the prions. People are
working on synthesising PrPsc (for
example, from normal PrPc by chemical
modification, or by genetically
modifying PrP to mis-fold
spontaneously), but I don't think anyone
has yet demonstrated infectivity this
way (unless it's quite
recent).

You might get a
higher chance of transmission with
human PrPsc, but getting hold of this
would be even tougher.

The
other possible use would be as a
terrorist weapon (assuming that
terrorists would have more resources to
produce PrPsc, would be prepared to
infect only a small random percentage
of a target population, and are happy to
wait several years). It would probably
be easier to lace food with PrPsc than
with most other, more easily-detected
toxins or
pathogens.

However, even as
a bioterrorism agent, prions are less
than ideal. They lack the immediate
impact of a bomb, which can kill as
many people far more easily, and which
elicits a much greater response than the
announcement that "of the 14 vCJD
deaths this year, it is estimated that
between 1 and 4 could be attributed to
the adulteration of foodstuffs by XYZ
seven years ago."

So, it is a
great piece of thinking (and, no doubt,
someone somewhere will be murdered
in this way, sometime), but I suspect
that many, many more people will be
murdered in other 'untraceable' ways
instead.

[Basepair], remember the PCR for making lots of DNA? In this era of genetic engineering, we could TODAY modify bacteria to churn out lots of prion protein. Then add a dab of the bad shape to it, wait for it to convert the rest, and then feed the victim the whole batch (perhaps over more than one meal). I strongly suspect that quantities of injested prions can be pretty directly related to the onset time of incapacitation. Provided you got those bacteria to make the proper variety, of course!

//In this era of genetic engineering, we
could TODAY modify bacteria to churn
out lots of prion protein.//We
could indeed, and several people of my
acquaintance do this routinely (though
not for malicious purposes). However,
in-vitro templating leading to large
amounts of infectious material has not
yet (though I may be out of date here)
been demonstrated. (I'll ask my wife -
her field.) But, I agree, if it's not yet
possible then it soon will be. (It is
probably more efficient to engineer in
amino-acid subsitutions which lead to
spontaneous mis-folding; but again, I
don't think this has been done
successfully yet to create an infectious
protein).

But then you're
looking at having a decent molecular
biology set-up (more so than if you're
just purifying PrPsc from animal
remains). I'm not saying it's not
possible, just that I can't imagine many
scenarios where someone would choose
this as a murder weapon.

If
you want a simpler way to *possibly*
kill someone after a long time, with
little risk of being caught, just
impregnate their pillow with a
radioisotope (stealable from any decent
lab) and hope they develop a brain
tumour, then remove the pillow. No
residual evidence, and the cause of
death is probably common enough to
avoid suspicion.